Downing Street is examining plans to encourage pensioners to retrain as teachers to fill gaps in the teaching of maths, engineering and English.

A group of Tory MPs from the 2020 Conservatives group who have been lobbying the No 10 policy director, Jo Johnson, presented to David Cameron the idea to retrain newly retired workers as teachers.

The 2020 Conservatives group of modernising MPs came up with the idea after the prime minister warned that too many teenagers were leaving the school with inadequate qualifications in maths and English. The scheme is designed to use the expertise of recently retired workers to fill teaching gaps and to raise standards in the sector.

George Freeman, a leading member of the 2020 Conservatives group who is MP for Mid Norfolk, told the Daily Telegraph: "The 2020 Conservatives is about the radical progressive centre ground of the parliamentary party, setting out bold ideas for unleashing social mobility and enterprise in 21st century Britain. We are setting out a programme of reform to show how economic and social enterprise and responsibility can go hand in hand in a competitive and compassionate Conservative Britain."

England came 26th in maths, 23rd in reading and 21st in science when the scores in the Programme for International Student Assessment (Pisa) were published in December. Michael Gove, the education secretary, said the results highlighted the need for his reforms, including establishing a more academic curriculum, the Guardian columnist Peter Wilby reported last month.